Hollow rail with three flanges



Oct. 7, 1958 J. c. ANDRIANNE 2,855,155

HOLLOW RAIL WITH THREE FLANGES Filed Oct. 4,. 1956 v 2 Sheets-Sheet 1 INVENTOR.

J. L.C. ANDRIANNE BY mu, W4 ya,

flft/ Oct- 7, 1958 J. L. c. ANDRIANNE 2,855,155

HOLLOW RAIL WITH THREE FLANGES Filed Oct. 4, 1956 2 Sheets-Sheet 2 IN V EN TOR.

J. L. c. ANDRIANNE HOLLOW RAIL WITH THREE FLANGES Jules Louis Charles Andrianne, Uccle, Belgium Application October 4, 1956, Serial No. 614,017

Claims priority, application Belgium October '7, 1955 2 Claims. (Cl. 238 133) A large number of types of rails having three flanges is already known in which the core may be solid, or be hollow and have a cylindrical axial hole. The cross-section of known rails shows that they are, generally, produced solely by assembling three single rails and have to be rolled in this form; it follows that the manufacture of a such rails is difficult and also very costly.

Moreover, a method of manufacturing rails having two flanges is also known in which use is made of a tube which is deformed to obtain the final profile of the rail.

In known hollow rails having two or three flanges, the thickness of the side walls at the site of the flanges is much greater than at the site of the webs. This is due to the fact that the underlying principle is that the flange is subjected to considerable wear and hence it must be thicker. In use, however, it has been found that before appreciable wear occurred the rails were destroyed by different effects, for example by fracture. Furthermore, to manufacture these rails use must be made of special tubes which are thicker at the points which will subsequently correspond to the flanges. Although some of the' above manufacturing processes have long belonged to the state of the art, the use of different wall thicknesses at the sites of the webs and the flanges has not hitherto been abandoned. Together with the difficult manufacture of the starting profile, relatively high weights are obtained and also in the majority of cases unfavorable distribution of the stresses and poor moments of resistance.

The subject of this invention is the provision of a rail with three flanges which, for the minimum weight that is the minimum expenditure of material, permits as great a load as possible and which offers an advantageous moment of resistance together with a regular distribution of stresses. Moreover, manufacture is rendered less costly since it affords the possibility of using a single starting profile.

According to the invention, in a hollow rail with three flanges obtained by deformation of a tube, the tubular starting profile and the final profile have a constant wall thickness over their entire periphery and the webs are limited on the inside and on the outside by arcs of a circle or by the chords which subtend the said arcs and whose circles to which these arcs belong have their centers situated on the axes of symmetry of the respective flanges opposite the webs which they form and are traced out with one or other of radii such that each external arc cuts the lateral faces of the two neighboring flanges at two symmetrical points and, if extended, meets the enclosing circumference corresponding to the tubular starting profile at symmetrical points.

According to one particular embodiment, the circles of which certain arcs or the chords which subtend them form the external walls of the webs, are traced out with a radius equal to the distance separating similar points situated respectively on the axes of symmetry of the flanges; these points may, for example, be situated outside or on the enclosing circumference, on the lines limiting the flanges, outside or, finally, inside these lines.

United States Patent "ice 2,855,155 Patented Oct. 7, 1953 By the combination according to the invention of the two characteristics, namely the same thickness of the walls and the special form of the webs, a profile is produced in which a particularly advantageous distribution of the isostatic lines is obtained. The width of the cluster of lines corresponds to the thickness of the walls so that undue stresses cannot form at any point; the use alone of walls of constant thickness would not be sufficient if the special form were not adapted according to the invention to the network of isostatic lines since there would then easily be a risk of premature fracture. The mass of material provided as in certain known rails at the site of the flanges is not really useful for the transmission of the stresses and has no'fayorable effect on the distribution of the stresses when the rail is worn.

According to an additional characteristic of the present invention the thickness of the walls is preferably selected so that the stresses on the inner surface of the profile at the site of the flanges are equal to zero and reach their maximum value at the outer surface of the profile, this value obviously remaining below the breaking load. In this Way only compression stresses occur in the flanges, which prove particularly favorable in the case of a load.

The present invention will be more easily understood by the description hereinbelow of the accompanying drawings which show solely by way of example some embodiments .of a rail according. to the invention.

Figure l is a diagrammatic view of the end of a rail with three flanges, with the arcs limiting the webs and the centers.

Figure 2 is similar to Figure 1 and shows the arrangement of the isostatic lines.

Figure 3 is similar to Figure l, but in this case the webs are limited by chords subtending the arcs.

Figures 4 and 15 are respectively similar views to Figures land 3, showing modified embodiments.

The rail is made from the ordinary tubular starting profile, the outer peripheral surface of which is shown diagrammatically in chain-dotted lines by the enclosing circumference 1; it has the same thickness 4 for the walls both at the flanges 2 and at the webs 3. The webs are limited by two arcs, 5 on the outside and 6 on the inside. The centers of the circles corresponding to these arcs are situated at 8 on the respective axes of symmetry 2' of the flanges and at the middle of the lines 7 limiting the said flanges 2; each center is on a flange 2 opposite a web 3. The extensions of each external arc of a circle 5 pass through the two similar points 8 of the two neighboring flanges situated on either side of the corresponding web 3, that is to say the circles to which the arcs 5 belong are traced with radii R equal to the distance between two similar points 8. The radii of the internal arcs 6 are smaller than the radii of the external .arcs 5 by a value equal to the thickness 4 0f the wall. The external arcs 5 cut the lateral faces 2a at two points 3a which are symmetrical in relation to the axes 2; the connection of the Webs to the flanges is progressive however.

In a variation the points 8 may be taken as centers and arcs be traced of a circle of radius R equal to the distance between two points 8'. The webs would be limited by arcs similar to 5a. Similarly, the points 8 or 8 could be taken as center and as radius the distance from the said center to one or other of the points 8', 8 which are similar and symmetrical in relation to the axis of symmetry passing through the center in question.

Figure 2 shows a rail as illustrated in Figure 1 and subjected to three equal forces 9 acting at 8 on the center of the flanges 2. In this case, the distribution of the isostatic lines is shown by chain-dotted lines. It will be seen that the isostatic curves coincide with the surfaces 5 of the webs and that especially favorable proportions are thus obtained. Moreover, the width of the cluster of isostatic 3 are curved and limited by arcs of a circle.

. 3 lines is equal to the thickness 4 of the wall of the rail having the maximum number of isostatic lines and the most favorable capacity of resistance for a minimum of weight and material. The profile of the rail is thus used to the maximum in its entirety under the, action of a load, thus giving the minimum fatigue of the material for a maximum load.

Figure 3 shows the straight cross-section of a rail similar to that shown in Figure 1; according to this modified embodiment, the webs 3 are limited on the outside and on the inside by the plane walls 5 and 6 constituted by the chords of the arcs 5 and 6 traced as explained hereinabove. i V

Figure 4 is similar to Figure 1, that is to say the webs In theembodiment illustrated, having as center the point 12 inside a flange land a radius equal to the distance between two similar points 12, the arcsSb limiting the webs to the outside and 6b. limiting the websto the inside are traced. The. axesuofsymmetry 2' when extended givesimilar points at 10. I Two other neighboring modified embodiments can be obtained by taking respectively the points 8 and 8'. as center and as radius the distances 8-10 and 8'.1 0.fro m these respective centers to the meeting point of the axis of symmetry which passes through the said centers with the arc 5b limiting the opposite web to the outside. The arcs limiting the webs being capable of being traced in this manner have not been included in the drawing in order not to overburden the figure.

Finally, in the modification shown in Figure 5, the webs are limited on the outside by the chords 5b subtending the arcs of a circle 5b traced from the points 12 as center with radii equal to the distance between the said points 12; on the inside, the webs are limited according to the thickness of the tube by parallels 6b to the chords 5b. t

The present invention is not restricted to the exemplified embodiments described hereinabove; without departing from the scope of the invention it is possible to select at any point whatsoever of the axes 2' the centers of the circles corresponding to the arcs limiting the webs and traced with a radius such that the are described to form the external wall of the webs meets the two neighboring lateral faces of the flanges and, if extended, cuts the enclosing circumference between the lateral faces of the flanges situated on either side of the axis on which the center is situated.

What I claim is:

1. A hollow rail comprising three rail heads symmetrically located with respect to the longitudinal axis of the rail obtained by deforming of a tube or by extrusion and having the same wall thickness over its entire periphery, the webs of the rail between two neighboring rail-heads being limited on the inside and on the outside by arcs of circles, the centers of the circles to which these arcs belong being on the respective axes of symmetry of the opposite rail-heads and each external are extension cuts the enclosing circumference of the rail in those parts comprised in the width of the rail-heads.

2. A hollow rail comprising three rail heads symmetrically located with respect to the longitudinal axis of the rail obtained by deforming of a tube or by extrusion and having the same wall thickness over its entire periphery, the webs of the rail between two neighboring rail heads being limited on the inside and on the outside by arcs of circles, the centers of the circles to which these arcs belong being on the respective axes of symmetry of the opposite rail heads and each external are extension cuts the enclosing circumference of the rail in those parts comprised in the width of the rail-heads and the centers of the circles to which belong the arcs limiting the webs, being located adjacent the rail heads.

References Cited in the file of this patent FOREIGN PATENTS 

